Your post made me think about my own obsession with eyeshadow, which is funny because prior to two years ago, I had zero interest in it...and now i'm in the hundreds for shadows (and of course, similars and dupes in there....even back ups). My problem too is the "being anxious" about running out, despite the fact that with the quantity I own, I probably will NEVER ever finish all of my shadows, much less all at once...yet I keep buying and buying.
So thank you for posting this! I'm going to do something similar...making this up on the spot so I hope it makes sense. lol.
I will dedicate myself to panning one shadow at a time.
once I pan the actual thing, I will look in my stash FIRST for a dupe, since I know there's many that are immensely similar. If a dupe is found, I will move onto using that eyeshadow.
If a dupe is not found, then I am allowing myself to either a) buy a higher-quality similar one (same here with MUFE. Their shadows are mindblowingly beautiful.) to replace it with, or allow myself to get a unique but WEARABLE color from burberry, nars, bobbi brown or tom ford, and only if nothing like it exists in my collection.
Before i make any purchases, however, I will check in with myself to see whether this is a color I still enjoy wearing (tastes change, after all), and if not, I am allowing myself to just not get anything. I don't want to keep my collection the same size it is..just slowly downsize it.
This way I can slowly make myself switch from low-mid end to mid-high end with my shadows, because I have found that with the exception of inglot, some MUG shadows, and a very limited selection of colors from mac, I just much prefer higher end shadows for their quality.
This process will be years in the making, since I am slow as heck in finishing stuff, but since i am not ready yet to destash them, my other option is to wear them and enjoy them.